If line b is perpendicular to line a, and line c is perpendicular to line a, what is the slope of line c?

Marcus needs to rewrite f(x) = x2 + 6x + 4 in vertex form.

The lengths of all sides of a triangle are integers when measured in decimeters. one of the sides has length of 1 dm and another of 3 dm. find the perimeter of the triangle.'

Atrain leaves little? rock, arkansas, and travels north at 90 kilometers per hour. another train leaves at the same time and travels south at 80 kilometers per hour. how long will it take before they are 680 kilometers? apart?